THE AUSTRALIAN Sports Anti-Doping Authority (ASADA) has slammed Essendon for its role in the supplements scandal that has ruined its 2016 season.

The Court of Arbitration for Sport (CAS) has suspended 34 past and present Bombers after finding them guilty of taking the banned substance Thymosin Beta-4 during the club's supplements program in 2012.

The CAS handed the players involved two-year bans backdated to March 31, with most of the suspensions ending on November 13 this year, taking into account provisional suspensions already served.

There's been widespread shock over the decision that has all but ruined the Bombers' 2016 season, but ASADA chief executive Ben McDevitt unleashed on the crippled footy club.

"This unfortunate episode has chronicled the most devastating self-inflicted injury by a sporting club in Australian history," McDevitt said in a statement released after the decision was made public.

The players – 12 of whom remain at Essendon, with five more at other AFL clubs – have received plenty of support from those inside and outside the footy world, but just like their club, they received no sympathy from ASADA.

McDevitt said that the players had been given significant anti-doping education by the AFL and ASADA, and those involved in the supplements saga had no grounds to claim that they were not at fault.

"Unfortunately, despite their education, they (the players) agreed to be injected with a number of substances they had little knowledge of, made no enquiries about the substance and kept the injections from their team doctor and ASADA," McDevitt continued.

"Of 30 ASADA testing missions during the period in question, none of the 18 players tested declared the injections, despite being asked each time whether they had taken any supplements.

"At best, the players did not ask the questions, or the people, they should have.

"At worst, they were complicit in a culture of secrecy and concealment."

At a media conference later, McDevitt said, "You simply cannot shift that personal responsibility to any support person, or any other person. Full stop.

"I feel for them quite strongly on a couple of fronts. But they obviously never paid due regard to the enormous possible ramifications and consequences of those decisions that they made when they signed on to a program involving injections of those substances."

The World Anti-Doping Authority (WADA), which appealed the AFL anti-doping tribunal's decision to clear the players of any wrongdoing in March 2015, also backed the suspensions handed down by the CAS.

In a statement, WADA director General David Howman said that the decision was a win for the anti-doping community and clean athletes around the world.

"If the AFL Tribunal’s decision had prevailed, it would have set a damaging precedent for future non analytical anti-doping cases; and, therefore, been detrimental for anti-doping efforts worldwide," he said.